1. Field of the Invention
The present invention pertains to the art of cooking appliances, and more particularly, to an airflow system for a cooking appliance employing convection heating techniques.
2. Discussion of the Prior Art
Cooking appliances that cook a food item through a forced-air convection airflow circulated in an oven cavity are known. Forced-air convection systems are incorporated into a wide array of cooking appliances, examples of which include single and double wall ovens, as well as slide-in and free standing ranges. Of the many design considerations that must be accounted for in forced air cooking systems, providing adequate heating to the convection airflow is perhaps one of the most important.
In order to perform a cooking operation, forced air convection systems circulate a heated or convection airflow about a cooking chamber portion of the appliance. Convection ovens typically employ one of three types of air circulation arrangements for heating the convection airflow. The first type of air circulation arrangement, passive circulation, takes advantage of naturally rising convection currents within the oven cavity. Passive circulation has no ability to control or otherwise manage the convection airflow. The second type of air circulation arrangement employs an unheated blower that forces air to circulate in the oven cavity. That is, the blower and heat source are separated in the appliance. Because the blower and heat source are separated, this arrangement provides limited control over air temperature distribution. The third type of air circulation arrangement forces air into the oven cavity after being heated by a heating element positioned proximate to the blower. The third type of arrangement is generally considered to provide the greatest heat transfer to the convection airflow.
In order to ensure a maximum heat transfer, the heating element is typically positioned about the blower in a series of stacked coils. That is, the coiled heating element is wrapped to form two or more spiraling, adjacent sections arranged about the blower. This construction creates a wall that covers roughly ⅔ of the airflow area. While effective at exposing the airflow to a heat source, the stacked coils actually create a significant airflow restriction. That is, the wall, while transferring heat to the airflow, simultaneously reducing the airflow from circulating about the oven cavity efficiently.
Based on the above, there still exists a need for an enhanced airflow arrangement in a convection oven. More specifically, there exists a need for an airflow arrangement that not only provides for maximum heat transfer, but significantly reduces any restrictions that may otherwise impede airflow circulation.